Gauge for oil tank



Feb. 16, 1960 H. J. ca. RUDOLF GAUGE FOR OIL TANK Filed July 2, 1956Brookline, Mass., as'signor to Applied g a corporation of Massa- Thisinvention relates to gauges for tanks for liquids, 'and moreparticularly for oil tanks such as are commonly used to hold a supply offuel oil for a house-heating burner. It is an object of. the inventionto provide a gauge whichv is simple, inexpensive to make, reasonably:accurate, and capable of being compactly packed for shipment.

According to the invention. a vertically slidable indicator is mountedon a column or post rising from a screw plug which is screwed into afilling hole in the tank. A light spring is arranged to draw theindicator slide upward. A light-weight strand or chain dangles from theindicator-slide through a hole in the plug. To the lower end of thestrand or chain'is secured a flexible elongated member which may have aspecific gravity only slightly "greater than that of the liquid'in'which it dangles, or may have a considerably higher specific gravity.Inthe latter case, the other end thereof is attached to and supported bya suitable float as hereinafter explained.

For a more complete understanding of the invention, reference may be hadto the following. description thereof,.- and to the drawing, of which--Figure 1 is an elevational view of a device embodying the invention;

.'Figure 2 is an elevation of a guide strip and indicator slide, and amodified form of pendant attached to the slide;

Figure 3 is an elevation of a screw plug and post to carry the guidestrip and indicator slide;

Figure 4 is a plan view of the guide strip;

Figure 5 is a perspective view of the indicator slide;

Figure 6 is a section of the post with other parts assembled thereon;

Figure 7 is a sectional view of an oil tank on which the device shown inFigure 1 is installed;

Figure 8 is a sectional view of a tank with a gauge having the form ofpendant shown in Figure 2; and

Figure 9 is an elevation of another modified form of pendant.

While the invention is applicable to tanks and liquids of various kinds,the embodiments hereinafter described are designed for use in gaugingthe depth of the pool of oil in the type of closed tank customarily usedin dwellings for supplying oil to the burner in a heating unit. Such atank is illustrated at 10 in Figures 7 and 8. Each such tank has a holein the top thereof which is screwthreaded to receive a gauge. Accordingto the invention, an improved gauge is provided which comprises a screwthreaded plug 12 serving as a base or support member for the rest of thegauging mechanism. The plug 12 has a central aperture in which issecured the lower end of an upright post 14. This post is in the form ofa split tube having a vertical slot 16 extending from end to end.Mounted on the post 14 is an assembly of parts as illustrated in Figure2, consisting of a front guide strip 18, an indicator member whichincludes an index 20, a spring 22 and an elongated connecting element24. The upper end of the vertical-guide strip 18 States Patent "ice isbent to a horizontal plane and is in the form of a disk 26 which fits inthe top of' the split tube 14 and is com nected to the vertical portionof the strip 18 by a neck 28 Which is slightly wider than the slot 16 ofthe post.

When theparts are assembled as indicated in Figure 6, "the side edges ofthe neck-ZUcngage in notches 30 in the edges of the slot 16 and hold theguide strip in front of the 'slot 16 and parallel to the axis of thepost. Notches 32 are provided in the disk 26 to receive a loop of thespring 22 atthe upperend thereof.

The indicator member is made of one piece of sheet metal such asaluminum. 'lt 'has a vertical shank 34 from the lower end of which adisk 36 projects horizontally to ride within the split tube 14. The disk36 has notches 38 in its edges'to receive a loop of the spring 22 at thelower end thereof. The tension spring'22 thus extends from the disk 26of the fixed guide strip to the disk 36 of the movable indicator memberand tends to move the latter upward. At the upper end of the shank 34 ofthe indicator member is a wider portion 39 which is bent over with anaperture lfl-through which the guide strip 18 passes. The extremity ofthe bent-over portion of the indicator member is the index 20. The disk36 at the lower end of the indicator member has a deep slot 42 toreceive the upper end of the flexible line 24 to attach the line to theindicator member. The flexible member may be of any suitable materialwhich is relatively light in weight. For example, a light variety ofchain of the type used for chain-pull light" sockets may be employed.ThlS' line extends from the indicator member down within the split tube14, through the aperture in the plug 12 and into the interior of thetank '10.

vfloat 46. The lengthof the chain 44 is approximately equal to half thedepth of the pool in the tank when the tank is filled to the prescribedfull-tank level with liquid such as oil. The combined length of the line24 and chain 44 is just enough to suspend the float clear of the bottomof the tank when the tank is empty. Under such circumstances the entireweight of the line 24, chain 44 and float 46 depends from the indicatormember and the gravitational pull of these parts stretches the coiledspring 22 so that the index is at its empty-tank position. When liquidis put into the tank, it picks up the float and as the level rises anincreasing portion of the chain 44 is supported by the float instead ofthe spring 22. As the gravitational pull on the spring is thusdiminished, the spring contracts and elevates the indicator member untilthe index 20 reaches the full-tank position when the tank has beenfilled. When this occurs, the entire weight of the chain 44 is carriedby the float 46 and the liquid in which the chain is immersed. The onlygravitational pull then acting on the spring is that due to its ownweight and that of the light flexible line 24, both of which arenegligible. Hence, when the tank is full there is little or noelongation of the spring and the indicator is as near to the top of thegauge casing as it is possible to get, and substantially the full heightof the casing is available for the scale marks. The scale divisionsbetween the full and empty marks are therefore of maximum size which isdesirable for easy reading.

An desired scale may be provided to cooperate with the index to indicatethe contents of the tank. For example a closed-end tube 50 oftransparent material such as lucite may be mounted on the plug 12 toenclose and protect the post 14 and the parts thereby. The index 20 isvisible through the wall of the tube on which suitable indicia 52 may beplaced as scale markings.

Another embodiment of the invention is illustrated in Figures 2 and 8.Instead of a chain with a float to support it when the liquid level ishigh, a flexible strip" 60 of material is suspended from the line 24 todangle vertically in the tank. This material should have a speeificgravity a little greater than that of the liquid in the tank so that thestrip'will hang verticallywhether the tank is empty or 'full; For use hedomestic oil-supply tank, the'strip-60 may be madejof ground-cork mixedwith a suitable synthetic resin which-is imprevious to the kind of oilwhich is to be put into the,tank. For this purpose abutadiene-acrylonitrile copolymer well-known by the name of Buna Nis'suitable. A mixture of this resin with ground cork, having a specificgravity from 0.95 to 1.05 is. available in the market. As the specificgravity of domestic fuel oil is about 0.8, a strip or strap ofthematerial described will hang vertically in-air or oil and can be readilycoiledv into a small compass for packing or shipping. The length of thestrip 60 is such that when suspended in an'empty tank it will extendfrom near the top-of the tank almost to the bottom thereof. The indexwill then be opposite the empty mark. As the tank is being filled withoil, an increasing part of the strip will be partially buoyed by the oilso that there will be a decreasing gravitational pull on the indicatormember. When the tank is full, a maximum amountof the strip 60 isimmersed in and partially buoyed by the oil, and the index 20' is at thefull-tank mark. In this form also of the invention the line 24 isselected to have negligible weight so that when the tank is full ofliquid, the pull on the spring spring coil and substantially the fullcasing is utilized for the scale.

l ,The dangling member 60 which displaces a varying amount of liquidaccording to the depth of the pool in the tank may be made'in otherforms. For example a flexible string of hollow beads 62 suitably linkedtogether may be employed, the beads being of metal or other relativelyheavy material which with the hollow interiors will average the desiredspecific gravity.

I claim:

1. A tank gauge comprising a support member height of the gauge 22 isnot enough to elongate the adapted to be mounted over a tank, anindicator member supported bysaid support member and movable thereonfrom a full-tank position to any empty-tank position, spring meanscarried by said support tending to move said indicator toward thefull-tank position, a flexible line of negligible weight depending fromsaid indicator, a heavier chain attached to and depending from saidflexible line, and a float attached to the free end of said chain, thecombined length of the flexible line and chain being such as to suspendthe float almost in contact with the bottom of the tank when the deviceis mounted over an empty tank, the length of the chain alone beingapproximately half the depth of the liquid in the tank when the tank isfull.=

2. A tank gauge comprising a support member adapted to be mounted over atank, an indicator member supported by said support member and movablethereon from a full-tank position to an empty-tank position, a tensionspring secured at its upper end to said support member and at its lowerend to said-indicator member, a flexible line of negligible weightdepending from said indicator and extending approximately half way tothe bottom of the tank when the gauge is mounted in place, a heavierchain attached to and depending. from the lower end .of said line, and afloat attached to the free end of said chain, the length of said chainfrom the line to the float being approximately half the height ofthetank.

References Cited in the file of this patent UNITED STATES PATENTS706,505 IWashington Aug. 5, 1902 2,029,405 Beadle Feb. 4, 1936 2,096,411St. John et al. Oct. 19, 1937 FOREIGN PATENTS 6,936 Great Britain May 8,1915 598.867 Great Britain Feb. 27, 1948

